Collision Energy Absorption Characteristics And Reliability Optimization Design Of Variable Cross Section Body Structure Under Stamping Constraints

With the improvement of Chinese industrial infrastructure and the continuous enhancement of its comprehensive national strength,Chinese automobile industry has also achieved remarkable development.As the most important automobile producer and consumer country in the world,Chinese collision safety issues have attracted widespread attention.Therefore,the optimized design of crashworthiness for automobiles that can ensure the safety of occupants and pedestrians is particularly important to reduce the mortality in traffic accidents,and to improve the overall competitiveness of Chinese automobile industry.With the increase in the requirements of both weight reduction level of body-inwhite and the crashworthiness,traditional equal-section thin-wall structures are gradually replaced by variable cross-sectional shape(VCS)thin-wall beam structures with complex cross-sectional shapes.VCS body structure has many design variables,complex manufacturing process constraints and other design problems,in addition,its collision energy absorption characteristics were not completely clear yet.Which makes it difficult that quickly and efficiently carry out optimized design and manufacturing of VCS body structure.Therefore,it is very important to establish a parametric model of VCS body structure under stamping constraints,explore its collision energy absorption characteristics,and develop reliability optimization design of VCS body structures under stamping constraints.The research works and innovative results of this article are mainly reflected in:The study used control parameters of the cross-sectional shape,scaling,thickness,etc.as design variables,a parametric modeling method was used to construct a CAD / CAE integrated parametric model of the VCS body structure;Assemblable constraint characteristics of VCS body structure,also fully considered manufacturing process constraints on the conceptual design stage,and obtain an implicit parametric model of the VCS body structure that meets the manufacturing constraints;combined the dynamic drop weight impact test,prepared a typical VCS sample to verify simulation accuracy of the VCS body structural parameterized model that has laid a foundation for the subsequent research.In order to solve the problem of constrained domain sampling,an improved constrained domain Latin square sampling algorithm is proposed.The test comparison of different cases shows that the algorithm has good versatility for multivariate and complex constrained sampling problems.The reliability optimization design of the structure provides the algorithm foundation;based on the ICD-LHS algorithm,the sample generation of the variable cross-section beam model under stamping constraints is carried out,and the variable cross-section beam samples that meet the manufacturing constraints are obtained.The effects of scaling,aspect ratio,thickness,cross-sectional shape,etc.on the deformation mode and impact energy absorption characteristics of the VCS body structure were explored.Using global sensitivity analysis,the qualitative description of various structural parameters on the impact energy absorption of the variable crosssection body structure was described.The influence rule of the characteristic obtains the reasonable design range of each structural parameter,which has a good guiding significance for the optimization design of the VCS body structure.Based on the collision energy absorption characteristics of the VCS body structure,the reasonable design range of each structural parameter was determined,and the sample points satisfying the stable deformation and punching constraints were obtained using the ICD-LHS algorithm,and the parametric model of the VCS body structure was used to quickly Solve the response value of the sample points,construct a highprecision kriging model;take the maximum energy absorption and the minimum mass as the optimization goals,and use the reliability optimization design method based on the kriging model to develop the reliability optimization design of the VCS body structure The design scheme with higher reliability significantly improves the crash resistance of the VCS body structure,taking into account both crash resistance and lightweight design.